Ok, I'm almost embarrassed to admit this with what probably seems like all of my dumb questions - but I am a nurse (just not a neuro nurse). I work on an adult critical care floor in a level one trauma center. I work 12 hour shifts and stand a great deal of that time. I am not currently diagnosed with MS but pretty sure that is what is going on.
My advice? Go for it - follow your dream. With the meds that you are on (and symptom free?) probably you could at least get your two years of med/surg experience in, and once you have that experience, the doors are wide open. As an RN, you could do many different positions - most of which do not require the long shifts standing on your feet. I'm back in school because I'd like to get my masters and be a Nursing instructor. If this is MS, the job would be Monday-Friday, school hours with at least some down time at the desk - I think it's do-able. Memory loss - well that could be a problem, but right now, note pads work great for me :). In the meantime, I'm thinking towards home health - you can sit down to chart, you've got time spent in your car driving from location to location, you basically make your own schedule which is great with the flexibility, on call usually once a week and the pay is phenomenal. There is also nurse educator, which someone else mentioned, or, you could work your way into administration, which is also pretty well paid and more desk related, but still with the option of some patient care, on your terms, when you visit your floor to help out.
The most important thing is the two years med/surg experience. Then, you can specialize - choose a field and make it your baby. I personally love med/surg, and I've been reluctant to leave the hospital, and probably won't any time soon. But I am thinking of other areas in case things get worse. The best part? The demand is huge - once you have your license, you'll never hurt for a job. You can travel (travel nurses make between $35 to $60 an hour with housing paid), you can do anything. :)